HF-SCF study of the ground state geometry and harmonic vibrational frequencies of borazine derivatives

The results of ab initio HF-SCF calculations of the B-monosubstituted borazine derivatives B3N3H5X (X = NH2, NO2, F, Cl, CN, NC, OH, N2 +, CCH, CHO, CH3, NH3 + and SiH3) are reported. The equilibrium geometries of the molecules were determined from gradient optimizations carried out employing the 6-31G* and 6-31G** basis sets. HF/6-31G* level calculations of disubstituted and trisubstituted F and Cl borazine derivatives and of trimethylborazine are included. The effects of the substituents on the geometry of the borazine ring were investigated. Vibrational frequencies were calculated for some B-monosubstituted molecules and the splittings of the degenerate modes of borazine due to symmetry lowering occurring in the B-monosubstituted molecules were examined. © 1993.